C # simple case -- unit converter,

C # simple case -- unit converter,

After several days of study, I wrote a simple winform application and pasted the source code to meet the demand.

The interface after the software is started is shown in:

The program consists of 6 labels, 8 comboboxes, 8 textBox, and 4 buttons. Set the ReadOnly attribute to true for the four textBox on the right.

When the software is started, comboBox can be used to display the default items. selectedIndex statement. By default, comboBox. selectedIndex = "-1" (no items are displayed by default). Change-1 to 0 to display the first item. Put the code in the Load event of the form. Code example:

private void MainForm_Load(object sender, EventArgs e)        {            comboBox1.SelectedIndex = 0;            comboBox2.SelectedIndex = 1;            comboBox3.SelectedIndex = 0;            comboBox4.SelectedIndex = 1;            comboBox5.SelectedIndex = 0;            comboBox6.SelectedIndex = 1;            comboBox7.SelectedIndex = 0;            comboBox8.SelectedIndex = 1;        }

　　

Press the OK button to execute the conversion function. Convert the calculation result to the string type and assign it to textBox. Text. code example:

Private void button4_Click (object sender, EventArgs e) {string str1, str2; str1 = Convert. toString (comboBox7.SelectedItem); str2 = Convert. toString (comboBox8.SelectedItem); double d1, d2; if (textBox7.Text = "") {textBox7.Text = "1"; d1 = 1;} else d1 = Convert. toDouble (textBox7.Text); if (str1 = str2) {d2 = d1; textBox8.Text = Convert. toString (d2);} else {if (str1 = "Celsius" & str2 = "Fahrenheit") {d2 = 1.8 * d1 + 32; textBox8.Text = Convert. toString (d2);} if (str1 = "degree Celsius" & str2 = "") {d2 = d1 + 273.15; textBox8.Text = Convert. toString (d2);} if (str1 = "Fahrenheit" & str2 = "Celsius") {d2 = (d1-32)/1.8; textBox8.Text = Convert. toString (d2);} if (str1 = "Fahrenheit" & str2 = "") {d2 = (d1-32)/1.8 + 273.15; textBox8.Text = Convert. toString (d2);} if (str1 = "" & str2 = "") {d2 = d1-273.15; textBox8.Text = Convert. toString (d2);} if (str1 = "" & str2 = "Fahrenheit") {d2 = (d1-273.15) * 1.8 + 32; textBox8.Text = Convert. toString (d2 );}}}

 

In the input box, do not enter keys other than the backspace key, number key, or decimal point key (for temperature conversion, you can enter a negative number) to prevent program errors caused by non-numeric characters. Add the relevant code to the keypress event. The code example is as follows:

Private void textBox1_KeyPress (object sender, KeyPressEventArgs e) {if (e. KeyChar! = '\ B' & e. KeyChar! = 46) // enter the backspace key and decimal point key {if (e. keyChar <'0') | (e. keyChar> '9') // enter 0-9 digits {e. handled = true ;}}}